Energy delivery devices and methods

ABSTRACT

This relates to methods and devices for achieving contact between the wall of a cavity or passageway and a medical device when used in tortuous anatomy.

BACKGROUND OF THE INVENTION

Asthma is a disease in which (i) bronchoconstriction, (ii) excessivemucus production, and (iii) inflammation and swelling of airways occur,causing widespread but variable airflow obstruction thereby making itdifficult for the asthma sufferer to breathe. Asthma is a chronicdisorder, primarily characterized by persistent airway inflammation.However, asthma is further characterized by acute episodes of additionalairway narrowing via contraction of hyper-responsive airway smoothmuscle.

Asthma is managed pharmacologically by: (1) long term control throughuse of anti-inflammatories and long-acting bronchodilators and (2) shortterm management of acute exacerbations through use of short-actingbronchodilators. Both of these approaches require repeated and regularuse of the prescribed drugs. High doses of corticosteroidanti-inflammatory drugs can have serious side effects that requirecareful management. In addition, some patients are resistant to steroidtreatment. The difficulty involved in patient compliance withpharmacologic management and the difficulty of avoiding stimulus thattriggers asthma are common barriers to successful asthma management.

Current management techniques are neither completely successful nor freefrom. side effects. Presently, a new treatment for asthma is showingpromise. This treatment comprises the application of energy to theairway smooth muscle tissue. Additional information about this treatmentmay be found in commonly assigned patents and applications in U.S. Pat.Nos. 6,411,852, 6,634,363 and U.S. published application nos.US-2005-0010270-A1 and US-2002-0091379-A1, the entirety of each of whichis incorporated by reference.

The application of energy to airway smooth muscle tissue, when performedvia insertion of a treatment device into the bronchial passageways,requires navigation through tortuous anatomy as well as the ability totreat a variety of sizes of bronchial passageways. As discussed in theabove referenced patents and applications, use of an RF energy deliverydevice is one means of treating smooth muscle tissue within thebronchial passageways.

FIG. 1A illustrates a bronchial tree 90. As noted herein, devicestreating areas of the lungs must have a construction that enablesnavigation through the tortuous passages. As shown, the variousbronchioles 92 decrease in size and have many branches as they extendinto the right and left bronchi 94. Accordingly, an efficient treatmentrequires devices that are able to treat airways of varying sizes as wellas function properly when repeatedly deployed after navigating throughthe tortuous anatomy.

Tortuous anatomy also poses challenges when the treatment devicerequires mechanical actuation of the treatment portion (e.g., expansionof a treatment element at a remote site). In particular, attempting toactuate a member may be difficult in view of the fact that the forceapplied at the operator's hand-piece must translate to the distal end ofthe device. The strain on the operator is further intensified given thatthe operator must actuate the distal end of the device many times totreat various portions of the anatomy. When a typical device iscontorted after being advanced to a remote site in the lungs, theresistance within the device may be amplified given that internalcomponents are forced together.

It is also noted that the friction of polymers is different from that ofmetals. Most polymers are viscoelastic and deform to a greater degreeunder load than metals. Accordingly, when energy or force is applied tomove two polymers against each other, a significant part of frictionbetween the polymers is the energy loss through inelastic hysteresis. Inaddition, adhesion between polymers also plays a significant part in thefriction between such polymers.

In addition to basic considerations of navigation and site access, thereexists the matter of device orientation and tissue contact at thetreatment site. Many treatment devices make contact or are placed inclose proximity to the target tissue. Yet, variances in the constructionof the treatment device may hinder proper alignment or orientation ofthe device. For example, in the case of a device having a basket-typeenergy transfer element that is deployed intralumenally, the treatmentmay benefit from uniform contact of basket elements around the perimeterof the lumen. However, in this case, design or manufacturing variancesmay tend to produce a device where the angle between basket elements isnot uniform. This problem tends to be exacerbated after repeatedactuation of the device and/or navigating the device through tortuousanatomy when the imperfections of the device become worsened throughplastic deformation of the individual components. Experiencedemonstrates that once a member becomes predisposed to splaying (i.e.,not maintaining the desired angular separation from an adjacentelement), or inverting (i.e., buckling inward instead of deployingoutward), the problem is unlikely to resolve itself without requiringattention by the operator. As a result, the operator is forced to removethe device from the patient, make adjustments, then restart treatment.This interruption tends to increase the time of the treatment session.

As one example, commonly assigned U.S. Pat. No. 6,411,852, incorporatedby reference herein, describes a treatment for asthma using deviceshaving flexible electrode members that can be expanded to better fill aspace (e.g., the lumen of an airway.) However, the tortuous nature ofthe airways was found to cause significant bending and/or flexure of thedistal end of the device. As a result, the spacing of electrode memberstended not to be even. In some extreme cases, electrode elements couldtend to invert, where instead of expanding an electrode leg would invertbehind an opposing leg.

For many treatment devices, the distortion of the energy transferelements might cause variability in the treatment effect. For example,many RF devices heat tissue based on the tissue's resistive properties.Increasing or decreasing the surface contact between the electrode andtissue often increases or decreases the amount of current flowingthrough the tissue at the point of contact. This directly affects theextent to which the tissue is heated. Similar concerns may also arisewith resistive heating elements, devices used to cool the airway wall byremoving heat, or any energy transfer device. In any number of cases,variability of the energy transfer/tissue interface causes variabilityin treatment results. The consequential risks range from an ineffectivetreatment to the possibility of patient injury.

Furthermore, most medical practitioners recognize the importance ofestablishing acceptable contact between the transfer element and tissue.Therefore, distortion of the transfer element or elements increases theprocedure time when the practitioner spends an inordinate amount of timeadjusting a device to compensate for or avoid such distortion. Suchaction becomes increasingly problematic in those cases where properpatient management limits the time available for the procedure.

For example, if a patient requires an increasing amount of medication(e.g., sedatives or anesthesia) to remain under continued control forperformance of the procedure, then a medical practitioner may limit theprocedure time rather than risk overmedicating the patient. As a result,rather than treating the patient continuously to complete the procedure,the practitioner may plan to break the procedure in two or moresessions. Subsequently, increasing the number of sessions posesadditional consequences on the part of the patient in cost, the residualeffects of any medication, adverse effects of the non-therapeuticportion of the procedure, etc.

In view of the above, the present methods and devices described hereinprovide an improved means for treating tortuous anatomy such as thebronchial passages. It is noted that the improvements of the presentdevice may be beneficial for use in other parts of the anatomy as wellas the lungs.

SUMMARY OF THE INVENTION

The present invention includes devices configured to treat the airwaysor other anatomical structures, and may be especially useful in tortuousanatomy. The devices described herein are configured to treat withuniform or predictable contact (or near contact) between an activeelement and tissue. Typically, the invention allows this result withlittle or no effort by a physician. Accordingly, aspects of theinvention offer increased effectiveness and efficiency in carrying out amedical procedure. The increases in effectiveness and efficiency may beespecially apparent in using devices having relatively longer active endmembers.

In view of the above, a variation of the invention includes a catheterfor use with a power supply, the catheter comprising a flexible elongateshaft coupled to at least one energy transfer element that is adapted toapply energy to the body lumen. The shaft will have a flexibility toaccommodate navigation through tortuous anatomy. The energy transferelements are described below and include basket type design, or otherexpandable designs that permit reduction in size or profile to aid inadvancing the device to a particular treatment site and then may beexpanded to properly treat the target site. The basket type designs maybe combined with expandable balloon or other similar structures.

Variations of the device can include an elongate sheath having a nearend, a far end adapted for insertion into the body, and having aflexibility to accommodate navigation through tortuous anatomy, thesheath having a passageway extending therethrough, the passageway havinga lubricious layer extending from at least a portion of the near end tothe far end of the sheath. Where the shaft is slidably located withinthe passageway of the sheath.

Variations of devices described herein can include a connector forcoupling the energy transfer element to the power supply. The connectormay be any type of connector commonly used in such applications.Furthermore, the connector may include a cable that is hard-wired to thecatheter and connects to a remote power supply. Alternatively, theconnector may be an interface that connects to a cable from the powersupply.

As noted below, variations of the device allow for reduce frictionbetween the shaft and sheath to allow relatively low force advancementof a distal end of the shaft out of the far end of the sheath foradvancement the energy transfer element.

Additional variations of the invention include devices allowing forrepeatable deployment of the expandable energy transfer element whilemaintaining the orientation and/or profile of the components of theenergy transfer element. One such example includes an energy transferbasket comprising a plurality of legs, each leg having a distal end anda proximal end, each leg having a flexure length that is less than afull length of the leg. The legs are coupled to near and far alignmentcomponents. The near alignment component includes a plurality of nearseats extending along an axis of the alignment component. The nearalignment component can be secured to the elongate shaft of the device.The far alignment component may have a plurality of far seats extendingalong an axis of the alignment component, where the plurality of nearseats are in alignment with the plurality of far seats. In thesevariations of the device, each distal end of each leg is nested within afar seat of the far alignment component and each proximal end of eachleg is nested within a near seat of the near alignment component suchthat an angle between adjacent legs is determined by an angle betweenadjacent near seats and the flexure length of each length is determinedby the distance between near and far alignment components.

One or both of the components may include stops that control flexurelength of each leg. Such a design increases the likelihood that theflexure of each leg is uniform.

An additional variation of the device includes a catheter for use intortuous anatomy to deliver energy from a power supply to a bodypassageway. Such a catheter includes an expandable energy transferelement having a reduced profile for advancement and an expanded profileto contact a surface of the body passageway and an elongate shaft havinga near end, a far end adapted for insertion into the body, theexpandable energy transfer element coupled to the far end of the shaft,the shaft having a length sufficient to access remote areas in theanatomy. The design of this shaft includes a column strength sufficientto advance the expandable energy transfer element within the anatomy,and a flexibility that permits self-centering of the energy transferelement when expanded to contact the surface of the body passageway.

BRIEF DESCRIPTION OF THE DRAWINGS

Each of the following figures diagrammatically illustrates aspects ofthe invention. Variation of the invention from the aspects shown in thefigures is contemplated.

FIG. 1 is an illustration of the airways within a human lung.

FIG. 2A is a schematic view of an exemplary system for delivering energyaccording to the present invention.

FIG. 2B is a side view of a device extending out of anendoscope/bronchoscope, where the device has an active distal end fortreating tissue using energy delivery.

FIGS. 3A-3G show various features of the device allowing for low forcedeployment of the energy element.

FIGS. 4A-4C illustrate various alignment components of the device.

FIGS. 4D-4E demonstrate the alignment components coupled to a leg of thedevice.

FIGS. 4F-4H illustrate an additional variation of an alignmentcomponent.

FIGS. 5A-5B is a variation of an energy transfer element according tothe present device.

FIGS. 5C-5D show variations in which the legs of the device are biasedto expand outward.

FIGS. 6A-6C show various basket configurations for the device.

FIGS. 7A-7D illustrate various features of variations of legs for usewith the present devices.

FIGS. 8A-8D show various junctions for use with the present devices toimprove alignment when the device is advanced through tortuous anatomy.

FIGS. 9A-9J are addition variations of junctions.

FIGS. 10A-10D shows additional variations of junctions for use in thepresent devices.

DETAILED DESCRIPTION

It is understood that the examples below discuss uses in the airways ofthe lungs. However, unless specifically noted, the invention is notlimited to use in the lung. Instead, the invention may haveapplicability in various parts of the body. Moreover, the invention maybe used in various procedures where the benefits of the device aredesired.

FIG. 2A shows a schematic diagram of one example of a system 10 fordelivering therapeutic energy to tissue of a patient for use with thedevice described herein. The illustrated variation shows, the system 10having a power supply (e.g., consisting of an energy generator 12, acontroller 14 coupled to the energy generator, a user interface surface16 in communication with the controller 14). It is noted that the devicemay be used with a variety of systems (having the same or differentcomponents). For example, although variations of the device shall bedescribed as RF energy delivery devices, variations of the device mayinclude resistive heating systems, infrared heating elements, microwaveenergy systems, focused ultrasound, cryo-ablation, or any other energydeliver system. It is noted that the devices described should havesufficient length to access the tissue targeted for treatment. Forexample, it is presently believed necessary to treat airways as small as3 mm in diameter to treat enough airways for the patient to benefit fromthe described treatment (however, it is noted that the invention is notlimited to any particular size of airways and airways smaller than 3 mmmay be treated). Accordingly, devices for treating the lungs must besufficiently long to reach deep enough into the lungs to treat theseairways. Accordingly, the length of the sheath/shaft of the device thatis designed for use in the lungs should preferably be between 1.5-3 ftlong in order to reach the targeted airways.

The particular system 10 depicted in FIG. 2A is one having a userinterface as well as safety algorithms that are useful for the asthmatreatment discussed above. Addition information on such a system may befound in U.S. Provisional application No. 60/674,106, filed Apr. 21,2005 entitled CONTROL METHODS AND DEVICES FOR ENERGY DELIVERY, theentirety of which is incorporated by reference herein.

Referring again to FIG. 2A, a variation of a device 100 described hereinincludes a flexible sheath 102, an elongate shaft 104 (in this example,the shaft extends out from the distal end of the sheath 102), and ahandle or other operator interface 106 (optional) secured to a proximalend of the sheath 102. The distal portion of the device 100 includes anenergy transfer element 108 (e.g., an electrode, a basket electrode, aresistive heating element, cyroprobe, etc.). Additionally, the deviceincludes a connector 110 common to such energy delivery devices. Theconnector 110 may be integral to the end of a cable 112 as shown, or theconnector 110 may be fitted to receive a separate cable 112. In anycase, the device is configured for attachment to the power supply viasome type connector 110. The elongate portions of the device 102 and 104may also be configured and sized to permit passage through the workinglumen of a commercially available bronchoscope or endoscope. Asdiscussed herein, the device is often used within an endoscope,bronchoscope or similar device. However, the device may also be advancedinto the body with or without a steerable catheter, in a minimallyinvasive procedure or in an open surgical procedure, and with or withoutthe guidance of various vision or imaging systems.

FIG. 2A also illustrates additional components used in variations of thesystem. Although the depicted systems are shown as RF type energydelivery systems, it is noted that the invention is not limited as such.Other energy delivery configurations contemplated may include or notrequire some of the elements described below. The power supply (usuallythe user interface portion 16) shall have connections 20, 28, 30 for thedevice 100, return electrode 24 (if the system 10 employs a monopolor RFconfiguration), and actuation pedal(s) 26 (optional). The power supplyand controller may also be configured to deliver RF energy to an energytransfer element configured for bipolar RF energy delivery. The userinterface 16 may also include visual prompts 32, 60, 68, 74 for userfeedback regarding setup or operation of the system. The user interface16 may also employ graphical representations of components of thesystem, audio tone generators, as well as other features to assist theuser with system use.

In many variations of the system, the controller 14 includes a processor22 that is generally configured to accept information from the systemand system components, and process the information according to variousalgorithms to produce control signals for controlling the energygenerator 12. The processor 22 may also accept information from thesystem 10 and system components, process the information according tovarious algorithms and produce information signals that may be directedto the visual indicators, digital display or audio tone generator of theuser interface in order to inform the user of the system status,component status, procedure status or any other useful information thatis being monitored by the system. The processor 22 of the controller 14may be digital IC processor, analog processor or any other suitablelogic or control system that carries out the control algorithms. U.S.Provisional application No. 60/674,106 filed Apr. 21, 2005 entitledCONTROL METHODS AND DEVICES FOR ENERGY DELIVERY the entirety of which isincorporated by reference herein.

FIG. 2B illustrates one example of an energy transfer element 108. Inthis example the energy transfer element 108 is a “basket-type”configuration that requires actuation for expansion of the basket indiameter. Such a feature is useful when the device is operatedintralumenally or in anatomy such as the lungs due to the varying sizeof the bronchial passageways that may require treatment. As illustrated,the basket contains a number of arms 120 which carry electrodes (notshown). In this variation the arms 120 are attached to the elongatedshaft 104 at a proximal end while the distal end of the arms 120 areaffixed to a distal tip 122. To actuate the basket 108 a wire or tether124 is affixed to the distal tip 122 to enable compression of the arms120 between the distal tip 122 and elongate sheath 104.

FIG. 2B also illustrates the device 100 as being advanced through aworking channel 32 of a bronchoscope 18. While a bronchoscope 18 mayassist in the procedure, the device 100 may be used through directinsertion or other insertion means as well.

As noted above, some variations of the devices described herein havesufficient lengths to reach remote parts of the body (e.g., bronchialpassageways around 3 mm in diameter). FIGS. 3A-3G illustrate variousconfigurations that reduce the force required to actuate the device'sbasket or other energy transfer element.

FIG. 3A illustrates a cross section taken from the sheath 102 andelongate shaft 104. As shown, the sheath 102 includes an outer layer 126and an inner lubricious layer 128. The outer layer 126 may be anycommonly known polymer such as Nylon, PTFE, etc. The lubricious layers128 discussed herein may comprise a lubricious polymer (for example,HDPE, hydrogel, polytetrafluoroethylene). Typically, lubricious layer128 will be selected for optimal pairing with the shaft 104. One meansto select a pairing of polymers is to maximize the difference in Gibbssurface energy between the two contact layers. Such polymers may also bechose to give the lubricious layer 128 a different modulus of elasticitythan the outer layer 126. For example, the modulus of the lubriciouslayer 128 may be higher or lower than that of the outer layer 126.

Alternatively, or in combination, the lubricious layers may comprise afluid or liquid (e.g., silicone, petroleum based oils, food based oils,saline, etc.) that is either coated or sprayed on the interface of theshaft 104 and sheath 102. The coating may-be applied at the time ofmanufacture or at time of use. Moreover, the lubricious layers 128 mayeven include polymers that are treated such that the surface propertiesof the polymer changes while the bulk properties of the polymer areunaffected (e.g., via a process of plasma surface modification onpolymer, fluoropolymer, and other materials). Another feature of thetreatment is to treat the surfaces of the devices with substances thatprovide antibacterial/antimicrobial properties.

In one variation of the invention, the shaft 104 and/or sheath 102 willbe selected from a material to provide sufficient column strength toadvance the expandable energy transfer element within the anatomy.Furthermore, the materials and or design of the shaft/sheath will permita flexibility that allows the energy transfer element to essentiallyself-align or self-center when expanded to contact the surface of thebody passageway. For example, when advanced through tortuous anatomy,the flexibility of this variation should be sufficient that when theenergy transfer element expands, the shaft and/or sheath deforms topermit self-centering of the energy transfer element. It is noted thatthe other material selection and/or designs described herein shall aidin providing this feature of the invention.

FIG. 3A also depicts a variation of a shaft 104 for use in the presentdevice. In this variation the shaft 104 includes a corrugated surface130. It is envisioned that the corrugated surface 130 may includeribbed, textured, scalloped, striated, ribbed, undercut, polygonal, orany similar geometry resulting in a reduced area of surface contact withany adjoining surface(s). The corrugated surface 130 may extend over aportion or the entire length of the shaft 104. In addition, the shape ofthe corrugations may change at varying points along the shaft 104.

The shaft 104 may also include one or more lumens 132, 134. Typically,one lumen will suffice to provide power to the energy transfer elements(as discussed below). However, in the variation show, the shaft may alsobenefit from additional lumens (such as lumens 134) to supportadditional features of the device (e.g., temperature sensing elements,other sensor elements such as pressure or fluid sensors, utilizingdifferent lumens for different sensor leads, and fluid delivery orsuctioning, etc.). In addition the lumens may be used to deliver fluidsor suction fluid to assist in managing the moisture within thepassageway. Such management may optimize the electrical coupling of theelectrode to the tissue (by, for example, altering impedance). Since thedevice is suited for use in tortuous anatomy, a variation of the shaft104 may have lumens 134 that are symmetrically formed about an axis ofthe shaft. As shown, the additional lumens 134 are symmetric about theshaft 104. This construction provides the shaft 104 with a crosssectional symmetry that aid in preventing the shaft 104 from beingpredisposed to flex or bend in any one particular direction.

FIG. 3B illustrates another variation where the sheath 102 includes anouter layer 126 and a lubricious layer 128. However, in this variationthe lubricious layer 128 also includes a corrugated surface 136. It isnoted that any combination of the sheath 102 and shaft 104 may have acorrugated surface.

FIG. 3C illustrates yet another aspect of construction of a sheath 102for use with the present device. In this variation, the sheath 102includes a multi-layer construction having an outer layer 126, one ormore middle layers 138. The middle layers 138 may be selected to haveproperties that transition between the outer layer properties and thelubricious layer properties, and improve the bonding between inner andouter layer. Alternatively, the middle layer 138 may be selected to aidin the column strength of the device. An example of the middle layerincludes Plexar PX 306, 3060, and/or 3080.

FIG. 3D depicts a variation of a shaft 104 for use with the devicesdescribed herein where the shaft outer surface comprises a lubriciouslayer 140. As illustrated, the shaft outer surface may also optionallyhave a corrugated surface 130. FIGS. 3E-3G illustrate additionalvariations of corrugated surfaces. As shown in FIGS. 3E and 3F, eitheror both the sheath 102 and the shaft 104 may have corrugated surfacesthat are formed by interrupting the surface. Naturally, different shapesand configurations may be otherwise constructed. FIG. 3G illustrates avariation where the sheath 102 comprises protrusions or spacer 142 toseparate the surfaces of the sheath/shaft.

FIGS. 4A-4D illustrate yet another feature that may be incorporated withany of the subject devices. FIG. 4A illustrates an example of analignment component 150. In this variation, the alignment component 150includes a plurality of seats 152 that nest electrode arms (not shown).As discussed herein, the seats 152 allow for improved control of theangular spacing of the arms. Moreover, the seats 152 permits design of adevice in which the flexure length of each of the arms of a basket typedevice is uniform (even if the tolerance of each arm varies). Though thealignment component 150 is shown as having four seats 152, any number ofseats may be employed.

The alignment component 150 also includes a stop 154. The stop 154 actsas a reference guide for placement of the arms as discussed below. Inthis variation, the stop 154 is formed from a surface of an end portion158. This end portion 158 is typically used to secure the alignmentcomponent 150 to (or within) the sheath/shaft of the device. Thealignment component 150 may optionally include a through hole or lumen156.

FIG. 4B illustrates another variation of an alignment component 152.This variation is similar to the variation shown in FIG. 4A, with thedifference being the length of the end portion 158. The smaller endportion 158 may optionally be employed when the component 150 is used atthe distal end of the device. In such a case, the component 158 may notbe attached to the sheath or shaft. In addition, the end portion 158 mayoptionally be rounded, for example, to minimize tissue trauma that maybe caused by the end of the device.

The alignment components 150 of the present invention may be fabricatedfrom a variety of polymers (such as nylon or any other polymer commonlyused in medical devices), either by machining, molding, or by cutting anextruded profile to length. One feature of this design is electricalisolation between the legs, which may also be obtained using a variationof the invention that employs a ceramic material for the alignmentcomponent. However, in one variation of the invention, an alignmentcomponent may be fabricated from a conductive material (e.g., stainlesssteel, polymer loaded with conductive material, or metallized ceramic)so that it provides electrical conductivity between adjacent electrodelegs. In such a case, a power supply may be coupled to the alignmentcomponent, which then electrically couples all of the legs placed incontact with that component. The legs may be attached to the conductivealignment component with conductive adhesive, or by soldering or weldingthe legs to the alignment component. This does not preclude the legs andalignment component form being formed from one piece of metal.

Devices of the present invention may have one or more alignmentcomponents. Typically the alignment components are of the same sizeand/or the angular spacing of the seats is the same. However, variationsmay require alignment components of different sizes and/or differentangular spacing. Another variation of the invention is to have the seatsat an angle relative to the axis of the device, so as to form ahelically shaped energy delivery element.

FIG. 4C illustrates another variation of an alignment component 150. Inthis variation, the alignment component 150 includes four seats 152.This variation includes an alignment stop 154 that protrudes from thesurface of the component 150. In addition, the end portion 158 of thealignment component 150 is also of a cross section that may improvestrength of the connection between the component and the sheath/shaft.In this case, the end portion 158 allows for crimping of thesheath/shaft. Optionally as shown, radial protrusions 178 at the rightof the end portion 158 may be included to allow heat bonding of thealignment component to the shaft. In this case, the shaft may be apolymer with a melting temperature lower than that of the alignmentcomponent. When constrained to be coaxial, heat, and if necessary axialpressure, may be applied to join the two components.

FIG. 4D illustrates the protrusion-type stop 154 that retains a notch162 of the electrode leg 160. This mode of securing the electrode leg160 provides a “redundant-type” joint. In one example, the leg 160 issecured to the alignment component 150 using a sleeve (not shown) placedover both the leg 160 and alignment component 150 with or without theuse of an adhesive within the sleeve. The notch 162 in the leg 160 isplaced around the protrusion-type-stop 154. As a result, the notch-stopinterface prevents the leg from being pulled from the device and isespecially useful to prevent the proximal or near ends of the legs fromseparating from the device. It is noted that this safety feature isespecially important when considering that if the proximal/near ends ofthe legs separate and hook on the anatomical passage, it may bedifficult or impossible to remove the device from the passage. Such afailure may require significant medical intervention.

FIG. 4E illustrates one example of a leg 160 affixed to near/proximaland far/distal alignment components 144, 146. As shown, the leg 160 mayhave an insulated portion 164 and an exposed portion 166 that formelectrodes. The near and far ends of the leg 160 are secured torespective alignment components 144, 146. In this example, sleeves 168and 170 cover the leg and alignment component. As noted above, one orboth of the alignment components may be electrically conductive toprovide power to the electrodes. Furthermore, adhesive (e.g.,cyanoacrylate, UV-cured acrylic, epoxy, or any such adhesive) may alsobe used to secure the leg to the components.

Additionally, the alignment components may be designed such that thesleeves may be press or snap fit onto the alignment components,eliminating the need for adhesively bonding the sleeves to the alignmentcomponents. FIG. 4F illustrates a perspective view of an end portion ofan alignment component 150 having one or more slots 186 to create endportion segments 184. The slots 186 permit deflection of the end portionsegments 184 to allow sliding of a sleeve or hypotube (either a near orfar sleeve 168 or 170) over the end portion. FIG. 4G shows a crosssectional view of the component 150 of FIG. 4F. As shown, once advancedover the end portion segment 184, the sleeve or hypotube becomes securedto the component 150. To lock the sleeve in place, an insert or wiremember 124 (not shown) is placed in the through hole or lumen 156. Theinsert or wire member prevents inward deflection of the end portionsegments 184 thereby ensuring that the sleeve or hypotube remainssecured to the component 150.

FIG. 5A shows a cross sectional view of two legs 160 attached toalignment components 144, 146. The sheath and shaft have been omittedfor clarity. The flexure length 164 of the leg 160 is defined as thelength between the alignment components 144, 146 over which the leg mayflex when the proximal and distal ends are moved closer to one another.As noted above, the alignment components permit the flexure length 164of the legs 160 to be uniform even if the leg lengths vary. The flexurelength 164 is essentially set by the longest leg, the shorter legs mayfloat between the stops 154 of the alignment components 144, 146. As anadditional measure to prevent the legs 160 from inverting, the lengthsof the sleeves 168 and 170 may be selected to be less than the length ofthe respective alignment components 144, 146 (as shown in the figure).The tendency of the leg to deflect outward can be improved by selectingthe sleeve length as such. When the legs 160 expand they are supportedby their respective seat on the interior side but unsupported on outerside. In yet another variation, the the seats can slant to predisposethe arms to deflect in a desired direction. For example, as shown inFIG. 5C, the seats 152 can slant as shown to predispose the legs 160 tooutward deflection. Such a construction can be accomplished by machiningor by drafting a molded part in the direction of the catheter axis. Asshown in FIG. 5D, the leg can have a slight bend or shape thatpredisposes the legs to bow outward.

FIG. 5B illustrates the variation of FIG. 5A in an expanded state. Asshown, the device may have a wire 124 or other similar member thatpermits movement of the far alignment component 146 relative to the nearalignment component 144. As noted herein, the wire 124 may beelectrically conductive to provide power to electrodes on the device.FIG. 5B also illustrates a ball tip 148 at the end of the device. Theball tip 148 may serve as a means to secure the wire 124 as well asproviding an atraumatic tip for the device.

Variations of the wire 124 may include a braided or coiled wire. Thewire may be polymer coated or otherwise treated to electrically insulateor increase lubricity for easier movement within the device.

To expand the energy transfer element 108, the wire 124 may be affixedto a handle 106 and actuated with a slide mechanism 114 (as shown inFIG. 2A.) In an alternative design, the wire 124 may be affixed betweenthe handle 106 and the distal end of the energy transfer element 108. Insuch a case, the slide mechanism 114 may be affixed to the shaft 104.Movement of the slide mechanism 114 causes expansion of the element 108as the shaft causes movement of the proximal end of the energy transferelement (being fixed to the shaft) relative to the distal end of theenergy transfer element (being fixed to the wire 124. In an additionalvariation, movement of the slide 114 may have two outcomes: 1) advancingthe energy transfer element out of the sheath; and 2) subsequentlyexpanding the energy transfer element. Such constructions are disclosedin U.S. patent application Ser. No. 09/436,455 filed Nov. 8, 1999 theentirety of which is incorporated by reference herein.

FIG. 6A illustrates a variation of an energy transfer element 108 inwhich the legs 160 have a pre-determined shape. This shape may beselected as required for the particular application. As shown, thepredetermined shape provides a certain length of the electrode 166 thatmay be useful for treatment of a long section of tissue.

FIG. 6B illustrates another variation of the energy transfer element108. In this variation, the legs 160 extend out of openings 180 in thesheath 102 (in other variations, the legs may extend out of openings inthe shaft). Accordingly, the alignment components and other parts of thedevice would be located within the sheath 102.

FIG. 6C illustrates yet another variation of an energy transfer element108. In this variation, the basket is connected at a proximal end andopened at a distal end. The electrode legs 160 only have a singlealignment component 150. The conductive member (or wire) may be locatedwithin the shaft 104. In this variation, advancement of the energytransfer element 108 out of the sheath 102 causes expansion of theelement. The energy transfer elements may be predisposed or springloaded to bow outward when advanced from the sheath.

FIG. 7A illustrates an example of a leg 160 with an energy element 180coiled around the leg 160. In this example, the energy element 182 usesconductive heating and comprises a resistance heating element coiledaround the leg 160. FIG. 7B illustrates a variation of the inventionhaving an RF electrode attached to the basket leg 160. The RF electrodemay be attached to the basket leg 160 via the use of a fastener. Forexample, the electrode may be attached via the use of a heat shrinkfastener, (e.g., polymeric material such as PET or polyethylene tubing).Alternatively, as discussed above, the entire leg may be a conductivemedium where a non-conductive coating insulates the majority of the legleaving the electrode portion uninsulated. Further examples of energytransfer element configurations include paired bipolar electrodes, wherethe pairs are leg to leg or within each leg, and large matrices ofpaired electrodes affixed to a variety of expanding members (balloons,mechanisms, etc.)

FIG. 7C illustrates a variation of the invention having thermocoupleleads 172 attached to an electrode 166 or leg of the device. The leadsmay be soldered, welded, or otherwise attached. This variation of theinvention shows both leads 172 of the thermocouple 174 attached inelectrical communication to a leg 160 at separate joints (or the leadsmay be separated but the solder on each connection actually flowstogether). In this case, the temperature sensor is at the surface of theleg. This variation provides a safety measure in case either jointbecomes detached, the circuit will be open and the thermocouple 174stops reading temperature. Such a condition may be monitored via thepower supply and allow a safe shutdown of the system.

By spacing the leads of the thermocouple closely together to minimizetemperature gradients in the energy transfer element between thethermocouple leads, thermoelectric voltage generated within the energytransfer element does not compromise the accuracy of the measurement.The leads may be spaced as close together as possible while stillmaintaining a gap so as to form an intrinsic junction with the energytransfer element. In another variation of the device, the thermocoupleleads may be spaced anywhere along the tissue contacting region of theenergy transfer element. Alternatively, or in combination, the leads maybe spaced along the portion of an electrode that remains substantiallystraight. The intrinsic junction also provides a more accurate way ofmeasuring surface temperature of the energy transfer element, as itminimizes the conduction error associated with an extrinsic junctionadhered to the device.

The thermocouple leads may be attached to an interior of the leg orelectrode. Such a configuration protects the thermocouple as the deviceexpands against tissue and protects the tissue from potential trauma.The device may also include both of the thermocouple leads as having thesame joint.

The devices of the present invention may use a variety of temperaturesensing elements (a thermocouple being just one example, others include,infrared sensors, thermistors, resistance temperature detectors (RTDs),or any other component capable of detecting temperatures or changes intemperature). The temperature detecting elements may be placed on asingle leg, on multiple legs or on all of the legs.

The present invention may also incorporate a junction that adjusts formisalignment between the branching airways or other body passages. Thisjunction may be employed in addition to the other features describedherein. FIG. 8A illustrates a device 100 having such a junction 176allowing alignment of the device to closely match the alignment of theairway. It is noted that the present feature also benefits those casesin which the pathway and target site are offset as opposed to having anangular difference.

The junction 176 helps to eliminate the need for alignment of the axisof the active element 108 with the remainder of the device in order toprovide substantially even tissue contact. The junction may be a joint,a flexure or equivalent means. A non-exhaustive listing of examples isprovided below.

The legs 160 of the energy transfer element may have various shapes. Forexample, the shapes may be round, rounded or polygonal in cross section.Additionally, each leg may change cross section along its axis,providing for, for example, electrodes that are smaller or larger incross section that the distal and proximal portions of each leg. Thiswould provide a variety of energy delivery characteristics and bendingprofiles, allowing the design to be improved such that longer or widerelectrode configurations can be employed. For example, as shown in FIG.7D, if the cross-sectional thickness of the electrode portion 166 of theleg 160 is greater than the cross-sectional thickness of the distal andproximal portions of the leg, the leg would be predisposed to bowoutward in the distal and proximal sections, while remaining flatter inthe electrode area of the leg, potentially providing improved tissuecontact.

As for the action the junction enables, it allows the distal end of thedevice to self-align with the cavity or passageway to be treated,irrespective of the alignment of the access passageway. FIG. 8Aillustrates an example of where the access passageway and passageway tobe treated are misaligned by an angle α. In the example shown in FIG.8B, the misalignment angle α is greater than the angle illustrated inFIG. 8A. Yet, the energy transfer element 108 of the treatment device100 remains substantially aligned with the target area.

FIGS. 8C and 8D illustrate an additional variation of the junction 176.In this variation the junction 176 may be reinforced with a reinforcingmember 230. The reinforcing member may have some degree of flexibilityto navigate the tortuous anatomy, but the flexibility will be less thanthe junction 176. As shown in FIG. 8C, the reinforcing member 230maintains the device shaft 104 in an aligned position, preferably forinsertion, removal, and or navigation of the device. When desired, thereinforcing member 230 may be removed from the junction 176 asillustrated in FIG. 8D. Accordingly, upon removal, the device is free toflex or orientate as desired. Furthermore, the reinforcing member may bereinserted within the junction 176 when repositioning or removing thedevice from the target site. In additional variations, it iscontemplated that the reinforcing member may be placed external to thedevice/junction.

FIGS. 9A-91 illustrate additional junctions for use in the devicesdescribed herein. As for these examples, FIG. 9A illustrates a junction176 in the form of a plurality of turns or coils 200 of a spring. Thecoil offers a flexure with 3-dimensional freedom allowing realignment ofthe active end of the subject device in any direction. Of course, asimple hinge or universal joint may also be employed.

The length of the junction (whether a spring junction or some otherstructure) may vary. Its length may depend on the overall systemdiameter. It may also depend on the degree of compliance desired. Forexample, with a longer effective junction length (made by extending thecoil with additional turns), the junction becomes less rigid or more“floppy”.

In any case, it may be desired that the junction has substantially thesame diameter of the device structure adjacent the junction. In thisway, a more atraumatic system can be provided. In this respect, it mayalso be desired to encapsulate the junction with a sleeve or covering ifthey include open or openable structures. Junction 176 shown in FIGS. 8Aand 8B is illustrated as being covered. A covering can help avoidcontaminating the joint with body fluid or debris which could compromisejunction function.

Some of the junctions are inherently protected. Junction 176 shown inFIG. 9B comprises a polymer plug 220 or a section of polymer having adifferent flexibility or durometer than adjacent sections. When aseparate piece of polymer is to be employed, it can be chemically,adhesively, or heat welded to adjacent structure; when the junction isformed integrally, this may be accomplished by selective vulcanizing, orreinforcement (even with a braid or by other means of forming acomposite structure). Generally, it is noted that any connection ofpieces or construction provided may be produced by methods known bythose with skill in the art.

As for junction 176 shown in FIG. 9C, it is formed by removing sectionsof material from the body of the device. Openings 218 formed at thejunction may be left empty, covered or filled with a more compliantmaterial. FIG. 9D also shows a junction 176 in which openings areprovided to provide increased flexibility. Here, openings 218 are offsetfrom each other to form a sort of flexible universal joint. In eitherjunction variation shown in FIG. 9C or 9D, the size, number shape, etc.of the opening may vary or be tuned as desired.

FIG. 9E shows a junction 176 in the form of a bellows comprisingplurality of pleats 216. Here too, the number of pleats, etc. may bevaried to achieve desirable performance.

Junction 176 in FIG. 9F shows a true “joint” configuration. In thiscase, it is a universal joint provided by ball 204 and socket 206. Theseelements may be held together by a tie wire 208, possibly with caps 210.Other configurations are possible as well.

FIG. 9G illustrates a junction 176 in the form of a reduced diametersection 202. This variation offers greater flexibility by virtue of itsdecreased moment of inertia at the junction. While section 202 isintegrally formed, the related junction 176 in FIG. 9H is formed from ahypotube or wire 212 having an exposed junction section 214 on the shaft104. Variations of the invention will permit a junction having a reducedbending moment of inertia section as compared to the remainder of thedevice and/or shaft of the device. Reducing the bending moment ofinertia may be accomplished in any number of ways. For example, therecould be an area of reduced diameter, a section of material having alower modulus, a section having a different shape, a flexible jointstructure, etc. It should be noted that there are many additional waysto reduce the bending moment that will be readily apparent to thoseskilled in the art viewing the invention disclosed herein.

Yet another junction example is provided in FIG. 9I. Here junction 176comprises a plurality of wires 222, 224, 226. In one variation, thewires simply offer increased flexibility of the junction. In anothervariation, the wires serve as an “active” or “dynamic” junction. Thewires may be adjusted relative to one another to physically steer thedistal end of the device. This junction may be manipulated manually withan appropriate user interface—especially one, like a joy-stick, thatallows for full 3-dimensional or rotational freedom—or it may becontrolled by automation using appropriate hardware and softwarecontrols. Of course, other “dynamic” junctions are possible as well.

FIG. 9J shows another joint configuration 176 employing an externalsleeve 262 between sections of the shaft 104. A moveable wire 124 toactuate a distal basket or the like is also shown. The space between thewire and sleeve may be left open as shown, or filled in with a flexiblepolymer 264, such as low durometer urethane, a visco-elastic material,etc. Though not necessary, providing an internal member may improvesystem pushability. The sleeve itself will typically be a polymericsleeve. It may be heat-shrink material such as PET tubing; it may beintegrally formed with either catheter body portion and press fit orslip fit and glued over other etc.

Another variation of the junctions includes junctions variations wherethe shaft 104 is “floppy” (i.e., without sufficient column strength forthe device to be pushable for navigation). In FIG. 10A, a tether 232connects energy transfer element 108 to the shaft 104 of the device 100.The tether may simply comprise a flexible wire or cable, it may comprisea plurality of links, etc. The tether variation of the invention alsoaccommodates relative motion between the device and the body (e.g.,tidal motion of breathing, other muscle contractions, etc.) The tetherpermits the device to move relative to its intended treatment locationunless the user desires and uses the tether or the sheath to pull thedevice back or drive it forward. The tether may have an alignmentcomponent (not illustrated) at the near end of the energy transferelement 108.

To navigate such a device to a treatment site, the energy transferelement 108 and tether 232 may be next to or within the sheath 102. Inthis manner, the column strength provided by the sheath allows foradvancement of the active member within the subject anatomy.

The same action is required to navigate the device shown in FIG. 10B.What differs in this variation of the invention, however, is that the“tether” is actually a continuation of a highly flexible shaft 104. Inthis case, the shaft 104 of the device is shown with a thicker orreinforced wall. In such a device, the shaft carries the compressiveloads on the device back to its distal end.

Like the device in FIG. 10B, the devices in FIGS. 10C and 10D havehighly flexible shafts 104. However, instead of a stiffening externalsheath, the device may employ a stiffening obturator 230 within a lumenof the shaft 104. As shown in FIG. 10C, when the obturator 230 fills thelumen, the device is relatively straight or stiff. When the shaft iswithdrawn as shown in FIG. 10D, the distal end of the device is “floppy”or easily conformable to the subject anatomy. With the shaft advancedsubstantially to the end of the device, it offers ease of navigation;when withdrawn, it offers a compliant section according to an aspect ofthe present invention.

As for other details of the present invention, materials andmanufacturing techniques may be employed as within the level of thosewith skill in the relevant art. The same may hold true with respect tomethod-based aspects of the invention in terms of additional acts acommonly or logically employed. In addition, though the invention hasbeen described in reference to several examples, optionallyincorporating various features, the invention is not to be limited tothat which is described or indicated as contemplated with respect toeach variation of the invention.

Various changes may be made to the invention described and equivalents(whether recited herein or not included for the sake of some brevity)may be substituted without departing from the true spirit and scope ofthe invention. Also, any optional feature of the inventive variationsmay be set forth and claimed independently, or in combination with anyone or more of the features described herein. Accordingly, the inventioncontemplates combinations of various aspects of the embodiments or ofthe embodiments themselves, where possible. Reference to a singularitem, includes the possibility that there are plural of the same itemspresent. More specifically, as used herein and in the appended claims,the singular forms “a,” “and,” “said,” and “the” include pluralreferents unless the context clearly dictates otherwise.

1. A catheter for use with a power supply, the catheter comprising: an elongate sheath having a near end, a far end adapted for insertion into the body, and having a flexibility to accommodate navigation through tortuous anatomy, the sheath having a passageway extending therethrough, a flexible elongate shaft slidably located within the passageway and having an outer shaft surface; an energy transfer basket coupled to the shaft, the energy transfer basket comprising a plurality of legs adapted to apply energy to a body lumen, each leg having a distal end and a proximal end, each leg having a flexure length that is less than a full length of the leg; a near alignment component having a plurality of near seats extending along an axis of the alignment component, the near alignment component secured to the elongate shaft; a far alignment component having a plurality of far seats extending along an axis of the alignment component, where the plurality of near seats are in alignment with the plurality of far seats; a connector for coupling the energy transfer basket to a power supply; and where each distal end of each leg is nested within a far seat of the far alignment component and each proximal end of each leg is nested within a near seat of the near alignment component such that an angle between adjacent legs is determined by an angle between adjacent near seats and the flexure length of each length is determined by the distance between near and far alignment components.
 2. The catheter of claim 1, further comprising a lubricious layer on an outer shaft surface.
 3. The catheter of claim 1, where the far alignment component includes a distal stop and the near alignment component includes a proximal stop, such that the distal end of at least one of the legs contacts the distal stop and the proximal end of the same leg contacts the proximal stop to control a flexure length of each leg.
 4. The catheter of claim 1, further comprising a handle located at a near end of the sheath, and where the sheath comprises a length sufficient to access a bronchial passageway of at least 3 mm in diameter when inserted through a respiratory opening of a patient.
 5. The catheter of claim 1, further comprising a lubricious layer on a surface of the passageway extending from at least a portion of the near end to the far end of the sheath.
 6. The catheter of claim 5, where the elongate sheath comprises a second material exterior to the lubricious layer, the second material being different from the lubricious layer.
 7. The catheter of claim 6, where the second material comprises a higher modulus of elasticity than the lubricious layer.
 8. The catheter of claim 3, where the far alignment component comprises an electrically conductive material allowing electrical communication of each leg.
 9. The catheter of claim 1, further comprising an electrically conductive member electrically coupling the energy transfer basket to the connector.
 10. The catheter of claim 9, where the conductive member comprises a wire.
 11. The catheter of claim 10, where the wire comprises a first diameter and tapers to a second diameter, where the taper provides the catheter with increased flexibility towards the basket.
 12. The catheter of claim 11, where the conductive member is fixed relative to the near end of the sheath and a distal end of the basket structure, and where a proximal end of the basket structure is attached to the shaft, such that sufficient advancement of the shaft causes the proximal end of the basket structure to move relative to the distal end of the basket structure resulting in expansion of the basket.
 13. The catheter of claim 11, where the conductive member comprises a helically wound coil wire.
 14. The catheter of claim 11, further comprising at least one temperature detecting element located on at least one leg.
 15. The catheter of claim 14, where the temperature detecting element is located on an interior surface of the leg.
 16. The catheter of claim 15, where the temperature detecting element comprises a thermocouple having a first and second leads, where each lead of the thermocouple is separately attached to the leg such that the leg forms part of the thermocouple.
 17. The catheter of claim 5, where the elongate shaft further includes at least one protrusion on the outer surface of the elongate shaft, where the protrusion separates and reduces surface contact between the outer surface of the elongate shaft and the lubricious layer of the passageway.
 18. The catheter of claim 17, where the at least one protrusion comprises a plurality of protrusions.
 19. The catheter of claim 17, where the protrusion extends along length of the elongate shaft.
 20. The catheter of claim 5, where the elongate sheath further includes at least one spacer in the passageway, where the spacer reduces surface contact between the outer surface of the elongate shaft and the lubricious layer of the passageway.
 21. The catheter of claim 20, where the at least one spacer comprises a plurality of protrusions.
 22. The catheter of claim 21, where the spacer extends along a length of the passageway.
 23. The catheter of claim 1, where the passageway comprises a corrugated surface.
 24. The catheter of claim 1, where the outer shaft surface comprises a corrugated surface.
 25. The catheter of claim 1, where the elongate shaft comprises at least one lumen.
 26. The catheter of claim 25, where the elongate shaft comprises a plurality of lumens where each lumen is symmetric about a central axis of the elongate shaft.
 27. The catheter of claim 1, further comprising a fluid delivery port terminating at the far end of the sheath, where the fluid delivery port is adapted to be coupled to a supply of fluid.
 28. The catheter of claim 1, further comprising a suction port terminating at the far end of the sheath.
 29. The catheter of claim 1, further comprising a junction located between a distal end of the elongate shaft and a proximal end of the energy transfer basket, the junction having a greater degree of flexibility than a remainder of the shaft such that misalignment between the energy transfer basket causes bending at the junction prior to deformation of the energy transfer basket.
 30. The catheter of claim 1 where the near alignment component comprises at least one protrusion, and where at least one leg comprises a notched portion, where the notched portion of the leg interferes with the protrusion to prevent the leg from moving in an axial direction. 